Determining the Potential of Cost-Effective Water Conservation for the City of Houston
How much water-use conservation can be cost-effectively achieved by Houston Water?
A team of researchers led by Dr. Timothy T. Loftus, Professor of Practice in Geography and Water Resource Strategist for the Meadows Center, are developing a suite of water conservation program scenarios, tailored for the City of Houston, that individually and collectively indicate a positive benefit-cost ratio for project collaborator, Houston Water. This work is to be conducted on behalf of the Houston-Galveston Subsidence District.
The Water Conservation Tracking Tool (WCTT), a MS-Excel-based model that has been developed for the Alliance for Water Efficiency and in use since 2009, will be applied in developing conservation program scenarios. The model-based tool is designed to help a water service provider plan for and track water conservation program activity and results. The tool provides an analytical framework for estimating the effects that plumbing/appliance standards and planned conservation programs will have on future water use, utility costs and sales revenue and average customer rates and bills. The tracking tool evaluates these effects in terms of costs and benefits from the perspectives of the utility (and its ratepayers) and program participants. Costs and benefits are calculated separately for each conservation measure tested and thus, can be used to help screen measures and construct program portfolios.
Scenarios will be developed for residential meter-class accounts and commercial/institutional meter-class accounts. Separate scenarios will be tested for residential indoor and outdoor water use.
This project is funded by the City of Houston and the Houston-Galveston Subsidence District, as part of the District’s 2019 Water Conservation Grant Program.
The following tasks will be completed in order to estimate residential water use conservation potential:
- Study residential water use on a monthly basis to estimate average indoor vs. outdoor water use.
- Study 10 years of monthly water-use data and weather data to determine peak seasonal demand during both wet and dry years.
- Review available data to understand age of single- and multifamily housing stock.
- Explore various indoor-conservation measures using the WCTT to determine potential and efficacy for both single-family and multifamily residential accounts. Present water savings, benefit-cost ratio, and other relevant findings per specific measure in program scenario. Interpret results for Houston Water and develop preliminary context-sensitive recommendations.
Estimate commercial/institutional water use by sector/sub-sector and water-use conservation potential
The following tasks will be completed to estimate commercial/institutional water use by sector/sub-sector and water-use conservation potential:
- Using US Census Bureau data from the 2017 County Business Patterns, number of establishments and employment will be identified for the relevant commercial sectors/subsectors as defined by the North American Industry Classification System (NAICS; US Census Bureau) for the City of Houston. These data will serve to generate estimates of water use by commercial sector/subsectors to help prioritize conservation efforts and target post-project outreach and implementation efforts.
- Explore various indoor conservation measures using the WCTT to determine potential and efficacy for commercial and institutional accounts. Present water savings, benefit-cost ratio, and other relevant data per specific measure in program scenario. Interpret results for Houston Water and develop preliminary context-sensitive recommendations.
The following tasks will be completed to develop new data and estimate outdoor water use conservation potential for residential accounts:
- Employing a geographic information system (GIS), we will select up to five neighborhoods in Houston in order to create data for residential lot size, landscaped area, and turf area as a percentage of lot size. Neighborhoods will be selected from high water use city council districts.
- From the data created in the task above, outdoor conservation measures will be explored via the WCTT to determine their savings potential and their economic efficacy (i.e., benefit-cost ratio and net-present value of water savings).
- To the extent practicable, data and measures will be developed with particular groundwater-dependent areas in mind. That said, measures will be broadly applicable throughout Houston Water’s service area.